Equine Herpes Virus – Worth Worrying About?

Just the mention of EHV-1, the Equine Herpes Virus, is enough to strike fear in the heart of any horse owner.  But what IS it, really? And how do we keep our horses safe?

The fact is that many horses are infected with the virus as a foal, others in adult life.  Like herpes infections in humans, the virus often goes dormant but can resurface when the horse is stressed by training, transport, competition, herd dynamics, or other health conditions.  The EHV-1 strain can affect your horse in 3 different ways:

 

1) respiratory

2) foal abortion

3) neurologic, specifically herpes myeloencephalopathy (EHM)

The incubation period is 1-10 days, with shedding of the virus through nasal secretions typically taking place for another 10 days after the host is infected.  Some cases have been reported to shed the virus for as long as 28 days.  

Direct horse-to-horse contact facilitates exposure, and it’s possible for airborne particles expelled by coughing or sneezing to transfer to horses some distance away, although no one knows exactly how far.  But the virus can also be transmitted on physical objects, including our own hands, clothing and shoes, as well as grooming equipment, tack, buckets, rakes, hoses and water tanks, just to name a few. The virus can survive for 7 days on these objects under normal circumstances, and as long as 28 days under perfect conditions. 

Can you protect your horse with a vaccine?  Yes and no.  The vaccine won't STOP your horse from contracting the virus, but it may lessen the amount of virus shedding in secretions.  This may reduce the likelihood of infecting other horses, in turn preventing foal abortions, while also reducing the respiratory symptoms in the infected horse.

But NO vaccine can protect your horse from the neurologic form of the disease.  In addition, it has been suggested that frequent vaccination with killed virus vaccine may actually INCREASE the risk of EHV-1.  So now we ponder....to vaccinate or not to vaccinate.  

That decision is, ultimately, up to you.  Regardless, here are a few things you can do to reduce your risk of infection:

1)      Stay informed of an outbreak in your area.  All outbreaks for any equine-related disease in the U.S. are reported on this web site:  http://equinediseasecc.org/outbreaks.aspx.  

2)      If there is an outbreak in an area you’re planning to trailer to, your best defense is to just stay home.  

3)      If you've already paid your entry fees and are determined to go, heavily disinfect your stall, put tarps on shared walls of stalls, avoid 'hanging out' on your horse in the warm up pen, and don't let your horse sniff noses with anyone.  Avoid touching other horses, wash your hands frequently and thoroughly disinfect all of your tools and equipment frequently.

And, finally, do everything possible to lessen the possibility of stressing your horse and to strengthen his immune system.  Give him good nutrition, avoid changing feeds abruptly, keep him hydrated, give him plenty of rest, and condition him properly before taking him to the event.